Question

Lewis and Clark's exploration of the Missouri River was very important for the westward expansion of the United States. For example, the information they gained
A.
allowed the river to become a major transportation route for settlers of the Great Plains.
B.
prevented the British from expanding their settlements from the Pacific Northwest eastward.
C.
prevented the Native American tribes of the Rocky Mountains from harassing American settlers.
D.
allowed the river to become a major transportation route for the Army during the Mexican War.

Answer 1

A.

Lewis and Clark mapped the Missouri and the West, recorded routes, and provided geographic and ethnographic information that encouraged settlement and made river transport (later steamboat traffic) a practical route for Great Plains settlers.